The invention relates to improvements in apparatus for gathering and removing particulate material (for example, fragments of rock or coal) in underground excavations, strip mines, quarries and other establishments wherein large quantities of particulate material are to be collected and transported away in a controlled manner.
It is already known to combine a so-called advance working machine or mining machine for collection of coal or other particulate material with a conveyor the trailing end of which is located at the level of a platform or ramp forming part of the machine and serving to gather material which is removed from a mine face and/or is comminuted during forward movement of the machine. The ramp carries several elongated beam-shaped material transferring members which flank the trailing end of the conveyor and are movable relative to the platform in order to shift particulate material along the platform and onto the conveyor for transport in a direction counter to that of forward movement of the machine. The material transferring members have a substantially triangular cross-sectional outline, and each such member has a substantially upright front flank which faces the trailing end of the conveyor and a second flank which slopes downwardly from the upper end of the first flank in a direction away from the trailing end. It is further known to position a stationary barrier behind each material transferring member, i.e., the members approach the adjacent barriers during movement away from the trailing end of the conveyor. Each barrier can constitute a wall or a beam having a cross-sectional outline resembling that of a material transferring member.
An apparatus of the above outlined character is described and shown in published German patent application No. 35 46 192. The apparatus of this published application is designed in such a way that the material transferring members which flank the trailing end of the conveyor are pivotable along the upper side of the platform about vertical shafts at their rear ends (as seen in the direction of forward movement of the machine). The barriers are affixed to the platform, and the latter supports several pivotable material transferring members at each side of the trailing end of the conveyor. This contributes to complexity of the mechanism which is used to pivot the material transferring members. Thus, and since the material transporting members are placed rather close to the upper side of the platform (in order to sweep not only larger but also smaller particles toward and onto the conveyor), they are likely to jam or the prime mover or prime movers which are used to pivot such material transferring members must be designed to apply large forces with attendant consumption of substantial amounts of energy. The situation is analogous when one or more pivotable material transferring members are disposed only at one side of the trailing end of the conveyor. Moreover, the wear upon the shafts and bearings for the material transferring members is quite pronounced, the same as the wear upon the members themselves and upon the motion transmitting mechanism or mechanisms.
Commonly owned published German patent application No. 33 04 908 discloses a somewhat different apparatus wherein elongated material transferring members which flank the trailing end of the conveyor are reciprocable toward and away from the respective sides of the trailing end. The material transferring members have a triangular cross-sectional outline with a steeper flank facing toward and a less inclined flank sloping downwardly away from the respective side of the conveyor. One end of each material transferring member is connected with a reciprocable pusher. This creates problems when particulate material is wedged between the material transferring members and the platform of the advance working machine because the elongated members are subjected to pronounced bending stresses and undergo extensive wear. Furthermore, the means for driving the pushers is located in the region where particulate material gathers on the platform so that such driving means is rapidly contaminated and its parts are subjected to extensive wear as a result of contact with larger and smaller fragments of particulate material.